Prospective Study of the Robertshaw Endobronchial Catheter in Thoracic Surgery

Prospective Study of the Robertshaw Endobronchial Catheter in Thoracic Surgery Raymond C. Read, M.D., Cheryl D. Friday, M.D., and Carol N. Eason, M.D. ABSTRACT One hundred three men undergoing thoracotomy on a general thoracic surgery service received endobronchial anesthesia with 100% oxygen using the Robertshaw tube. Bronchial intubation was accomplished in all. However, cross-leak or difficulty with deflation necessitated discontinuance in 8, while Pao, values of 41 and 45 mm Hg caused abandonment in 2. There were no operative deaths. Surprisingly, hypoxemia in these patients related more to insufficient alveolar ventilation than to the venoarterial shunt.

In 1949, Carlens [4] devised a new flexible double-lumen endobronchial catheter for bronchospirometry that could be introduced without the need for fluoroscopy or bronchoscopy. The following year he and Bjork [2] reported having used it so as to avoid aspiration of infected material into the dependent lung during resection for suppurative pulmonary disease. They suggested intrabronchial hemorrhage or air leaks from enucleation of benign tumors as other indications. Jenkins and Clarke [8] in 1957 and Newman and associates [14], four years later, advocated routine use of the Carlens catheter in pulmonary operations because secretions could be confined to the operative side, ventilation was better with bronchopleural fistulas, tracheal or bronchial repair was facilitated, and adequate ventilation could be maintained during suction. Surgical advantages were: wider exposure, easier hilar dissection, no need to retract the lung, and ability to perform bronchial closure or open bronchoplasty. However, concern regarding inFrom the Surgical and Anesthesia Services, Veterans Administration Hospital, and the Departments of Anesthesiology and Surgery, University of Arkansas for Medical Sciences, Little Rock, AR. Presented at the Twenty-third Annual Meeting of the Southern Thoracic Surgical Association, Nov4-6,1976, Acapulco, Mexico. Address reprint requests to Dr. Read, Chief, Surgical Service, Veterans Administration Hospital, 300 East Roosevelt Rd, Little Rock, AR 72206.

156

creased resistance to air flow and difficulty in placement, especially with distorted carinae, prevented widespread adoption of this technique. These latter objections were largely removed with the introduction in 1962 of the inexpensive and reliable Robertshaw tube [161. Its advantages included wider lumens, allowing for l o ~ r resistance to gas flow and easy suctioning; absence of a carinal hook, allowing easier introduction and a flush bronchial closure in pneumonectomy; molded curvature to reduce kinking; and a slotted right tube to ensure inflation of the right upper lobe. Zeitlin and coworkers [23], Wood and colleagues [22], ancl Thomson and Campbell [201 have advocated the routine use of endobronchial anesthesia in thoracic surgery, claiming that gas exchange is better (because the lung is not retracted) than with endotracheal intubation. Despite these strong recommendations and the obvious advantage to the surgeon of being able to operate on a quiet, collapsed lung, the Robertshaw tube has not been widely adopted. Apart from a natural resistance to change, a number of obstacles still prevent widespread use of the Carlens tube methodology in thoracic procedures. First, its use only in isolated cases leads to frustration because the anesthesia staff requires considerable experience with the method before optimal results can be obtained. Second, anesthesiologists remain prejudiced about isolated experience with the Carlens catheter, being unaware of the many advantages of the less publicized Robertshaw tube. Finally, a real concern remains that the technique cannot be safe for everybody since, in certain patients with marginal pulmonary function, inflicting a functional pulmonary arteriovenous shunt through a whole lung might lead to potentially hazardous hypoxemia. The purpose of our investigation was to study prospectively a consecutive series of patients

157

Read, Friday, and Eason: Robertshaw Endobronchial Catheter

undergoing thoracotomy on a general thoracic surgery service to document the difficulties encountered by our anesthesia staff as well as the incidence of hypoxemia. We hoped to reassess the importance of the objections that continue to prevent widespread adoption of endobronchial anesthesia in thoracic surgery.

Methods The study covered 103 men scheduled to undergo thoracotomy, either for pulmonary resection (78) or for extrapulmonary thoracic disease (25), mainly esophageal, over the past 2 years. They ranged in age from 23 to 75 years (mean, 55). Arterial blood gas tensions were determined preoperatively, intraoperatively, and postoperatively (Table). Chest roentgenograms and standard pulmonary function studies were also obtained (Fig 1).Other measurements were taken commensurate with disease. Preanesthetic medication consisted of fentanyl and droperidol with atropine or scopolamine. Anesthesia was induced by nurse anesthetists and supervised by anesthesiologists, using intrave-

nous thiamylal, fentanyl, and droperidol. It was maintained with 0.5 to 2.5% Fluothane or enflurane in 50% nitrous oxide and oxygen until one-lung ventilation was instituted, when 100% oxygen was given. Supplementary fentanyl and droperidol were administered as necessary. Either succinylcholine or pancuronium was given to facilitate intubation and, as needed throughout the operation, for relaxation. Anesthesia times ranged from 120 to 380 minutes (mean, 237 min). Arterial blood samples were obtained from a radial artery. After induction of anesthesia the patients were intubated with either a right or left Robertshaw double-lumen endobronchial tube of appropriate size (generally large). Both cuffs were inflated, allowing each lung to be ventilated separately. Position and fit of the tube were carefully ascertained by auscultation of the chest, especially the upper lobes, first with both lungs inflated and then with each in turn collapsed and disconnected from the circuit. This maneuver was repeated after the patient was turned to the lateral position for operation. Ven-

Arterial Blood Gas Determinations in 103 Thoracotomy Patients Condition 1. Preoperative (room air) Mean Range SD 2. Intraoperative (both lungs 50% 0,) Mean Range SD 3. Intraoperative (left lung 100% 0,) Mean Range SD 4. Intraoperative (right lung 100% 0 2 ) Mean Range SD 5. Postoperative (room air) Mean Range SD SD = standard deviation.

No. of Patients 96

57

29

Po, (mm Hg)

Pco, (mm Hg)

PH

77.3 57-98 9.4

37 25.7-45.8 3.8

7.41 7.35-7.52 0.03

190 74-400 62.6

36.9 24.5-54.4 74

7.43 7.28-7.61 0.08

169 41-333 81.6

37.1 22.6-56.1 7.72

7.41 7.22-7.56 0.08

173 45-312 71.1

36.9 18.7-48.1 14.3

7.44 7.29-7.64 0.09

68.0 52-95 7.64

36.7 30-49 4.25

7.44 7.38-7.50 0.03

23

63

158 The Annals of Thoracic Surgery Vol 24

No 2 August 1977

0 0

0

a

0 0

0

0 0

0.0 .

0

OO 0

0

1 30

0

I

I

40

50

0 0

0.

0. 0 0 0.0

20

0

0 0.0

0

0

.

0.

O0 0 O . 0 0 moo

0

4

0

0 0.

0

I

60

0

's.

0

I 70

I

80

YEARS

Fig 1. Scatter of preoperative arterial oxygen tension values (room air), taken from the Table (item l ) ,to show number of measurements below 70 mm Hg in ourpatients, many of whom had emphysema; 60 mm Hg is a better cutoff for hypoxemia.

tilation was maintained manually with tidal volumes of 8 to 15 ml per kilogram of body weight at a respiratory rate of 12 to 15 per minute. An effort was made to obtain blood gas measurements, especially in those who showed arrhythmia, hypotension, or any ventilatory difficulty; in some instances this was not possible. In 11patients in this group, repeated adequate measurements were not possible. Lack of adherence to protocol by the anesthesiologist also reduced the volume of information. Finally, there were errors in sampling. In only 57% of the patients were the data considered to be adequate both before and after passage of the Robertshaw tube. Samples were obtained 15 minutes or more after tube positioning (Fig 2) and 15 minutes or more after one-lung anesthesia was induced (Fig 3). They were determined with an Instrumentation Laboratories 313 BG blood gas analyzer and corrected for the patient's temperature.

1

1

30

40

1 50

1

1

1

60

70

80

YEARS

Fig2. Variation in arterial oxygen tension in patients: with Robertshaw tube and both lungs ventilated with 50% oxygen. Note absenceof hypoxemia. Data from' the Table (item 2). 4 OC

RightLung

0

L e f t Lung o

0 0

0

0

30C

0.

0

0

s"F F

8"

0

0 2 oa

" 0 0

4000

0

0

0

YEARS

Fig3. Data taken from the Table (items3 and 4) to show wide range of arterial oxygen tensions during one-lung anesthesia with 100Yooxygen. Note the values below 60mm Hg, indicating rare but severe hypoxemia with this technique.

159 Read, Friday, and Eason: Robertshaw Endobronchial Catheter

Results It was possible to pass the Robertshaw tube into the bronchi in all 103 patients (57 left, 46 right). The "up" lung deflated satisfactorily in 75 when the respective lumen was disconnected from the anesthesia circuit. In the remaining 28 the lung did not collapse completely because, either separately or in combination, the contralateral bronchial cuff extended to obstruct the up bronchus or there was a cross-leak of gases. Deflation and reinflation of the cuff on the "down" ventilated lung bronchus, with or without passage of the tube farther up or down, produced a satisfactory fit without compromise of the up bronchus and without cross-leak in 18 patients. Deflation times ranged from 5 to 248 minutes (mean, 63). In the remaining 10 patients complete deflation was not possible despite manipulation; therefore, either the tube was withdrawn into the trachea, or the lung being operated on wasventilated along with the down lung. One-lung ventilation had to be abandoned because of hypoxemia in 2 other patients. The first, a 57year-old man undergoing lobectomy for cancer of the right lung, had that side completely collapsed, while the same lung was deflated in the second patient being operated on for esophageal stricture. In both, the tube was thought to be functioning properly with adequate ventilation of the down lung. However, the blood gas values showed otherwise. Three of 52 arterial P q determinations were less than 70 mm Hg (41,45, 54 mm Hg). Associated P c q readings were high (46,46,54 mm Hg) and pH values were reduced (7.30, 7.31, 7.33). Twelve of 52 arterial Po, readings were below 90 mm Hg, 8 being recorded in patients who were undergoing left lung ventilation; 9 patients were being operated on for pulmonary disease. Age range of these patients was 37 to 69 years with an average of 55 years. All 103 survived the operative procedure, which in the 78 having pulmonary resection consisted of lobectomy in 41, wedge or segmental excision in 26, pneumonectomy in 9, and biopsy in 2. Twelve patients died some months after operations, 8 from cancer of the lung, 3 from pulmonary fibrosis with insufficiency, and 1from cancer of the esophagus. No postoperative complications could be attributed to the use

of endobronchial anesthesia with the Robertshaw tube. Comment Our two-year experience with more than 100 consecutive patients operated on using endobronchial anesthesia has confirmed earlier work [8] demonstrating the many advantages to the surgeon and anesthesiologist of being able to ventilate each lung separately during operation. Shallow breathing is not required for better operative exposure. Our anesthesia staff were able to pass the Robertshaw tube in every instance, testifying to its facility. However, like Zeitlin and associates [23], we found the fit of this double-lumen catheter around the carina was initially unsatisfactory in approximately 25% of the patients, thus allowing a leak to the other side or interfering with deflation. Nevertheless, by manipulation from above, and in some instances with cooperation from the surgeon, fewer than 10% of these patients had to have one-lung anesthesia discontinued because of unsatisfactory fit. It may be that further development of the cuff and molding of these catheters will reduce this incidence. However, with distortion of the carinae from disease, it is likely that some few patients will continue on mechanical grounds to be unsuitable for endobronchial anesthesia. Bjork and Carlens [21, in their original paper regarding application of the double-lumen catheter to thoracic surgery, pointed out that a considerable amount of blood necessarily passes through nonventilated lung tissue when the bronchus to the side being operated on is occluded. They reported an instance of cyanosis and suggested that the atelectatic lung might have to be ventilated intermittently to avoid hypoxemia in patients with poor pulmonary reserve. This observation went unheeded by a number of investigators [l,3, 6, 8, 12-14, 201, one-lung anesthesia being conducted with 25% and 50% oxygen concentrations in the belief that blood flow through collapsed lung is negligible. Mechanisms responsible for this fortunate arrangement were believed to be hypoxic vasoconstriction, a reduced circulatory bed in diseased lung tissue, and gravitational deviation of blood to the dependent (ventilated) lung. More

160 The Annals of Thoracic Surgery Vol 24 No 2 August 1977

recently, intraoperative systemic arterial blood gas measurements have demonstrated that with one-lung anesthesia, hypoxemia (Pa% below 70 mm Hg) occurs relatively frequently unless 100% oxygen is used routinely [13]. Nevertheless, our own results confirm the fact [7, 9, 151 that although mean Paq is acceptable in this group of patients, a few have an alarmingly low value (see Fig 3 ) . In a previous study from this institution [71we observed that 60% of similar patients undergoing one-lung anesthesia shunted more than a third of their cardiac output through the unventilated lung, and in 25% the shunt fraction exceeded 40%. In the present study, hypoxemia on 100% oxygen was so severe in 2 patients that one-lung anesthesia was discontinued. There was an associated elevation of Pacq, which suggests that, despite high tidal volumes, alveolar ventilation in the down (ventilated) lung was inadequate apart from the added burden of the shunt. It is apparent that some patients [51 do not have enough functioning alveoli in the one ventilated down lung to prevent retention of the carbon dioxide normally excreted by its partner. Furthermore, Pao, cannot be raised to normal levels in these individuals because of the magnitude of the shunt (contributed by the up lung along with diseased areas in its downventilated partner). Thus, when the degree of shunt is extreme, increasing the F I will ~ not always prevent hypoxemia in these patients. The futility of attempting to raise P a q by increasing the F I to~ 1.0 has long been recognized in patients with large right-to-left intracardiac shunts and is becoming more commonly recognized in the adult respiratory distress syndrome. Hypoxemia was more common when the left lung was being ventilated alone. The sinistral predominance was more than can be accounted for by the right hemothorax being opened more frequently in thoracic procedures. Presumably, pulmonary insufficiency is more likely to become manifest in the smaller lung. Because hypercapnia has been observed only rarely [lo] during one-lung anesthesia, hypoxemia is usually attributed to the venoarterial shunt alone, without consideration of the role played by underlying disease in its ventilated partner.

In conclusion, our data show that in a small number of patients, hypoxemia, not present when both lungs are ventilated with 50% oxygen, appears despite an increase in FIQ to 1.0 when the same tidal volume is shifted to one lung, especially the left. There may have been ventilatory problems, such as kinking of tubes and inadequate removal of secretions, in these few cases, but our previous reports of this phenomenon, and those of others [7, 9, 15, 17-19, 211, point to a more fundamental difficulty. This could be related to the shifting of the large tidal volume from both lungs to one, thereby distending the ventilated lung and raising pulmonary vascular resistance, and thus diverting even more venous blood into the collapsed up lung [7].Positive end-expiratory pressure has similar limitations [MI. However, that this is not a1way:s the explanation can be inferred from our previous work [71, which demonstrated that the shunt volume increased in some patients when tidal volume, and therefore the distending pressure in the ventilated lung, fell from 15 to 8 ml/kg. Thus it is important to monitor Pa$, if necessary, with different tidal volume. In our previous study only 3 of 18 patients undergoing thoracic operations were found to have normal ventilatory indices preoperatively . Emphysemia and chronic bronchitis may, in a few patients, so reduce pulmonary function that one-lung ventilation fails to satisfy respiratory requirements. How can we eliminate these few instances of hypoxemia, since their occurrence inhibits routine application of endobronchial anesthesia? Temporary occlusion of the pulmonary artery while the bronchus is obstructed forces all the cardiac output to pass through the ventilated lung. A number of authors [7, 12, 15, 181 have reported on this maneuver. However, it entai1:s added dissection, and this is difficult to perform, especially in extrapulmonary procedures. Presently, we are investigating the possibility of balloon tamponade of the pulmonary artery to the lung being operated on, using modified Swan-Ganz catheters. References 1. Aalto-Setala M, Heinonen J: One lumen versu:j double-lumen endobronchial tubes in thoracic

161 Read, Friday, and Eason: Robertshaw Endobronchial Catheter

anaesthesia: a comparison of blood-gas tensions. Ann Chir Gynaecol Fenn 63:276, 1974 2. Bjork VO, Carlens E: The prevention of spread during pulmonary resection by the use of a double-lumen catheter. J Thorac Surg 20: 151,1950 3. Bonica JJ, Hall WM: Endobronchial anesthesia for intrathoracic surgery. Anesthesiology 12:344, 1951 4. Carlens E: A new flexible double-lumen catheter for bronchospirometry. J Thorac Surg 18:742,1949 5. Das BB, Fenstermacher JM, Keats AS: Endobronchial anesthesia for resection of aneurysms of the descending aorta. Anesthesiology 32: 152, 1970 6. Edwards EM, Hatch DJ: Experiences with doublelumen tubes. Anaesthesia 20:461, 1965 7. Flacke JW, Thompson DS, Read RC: Influence of tidal volume and pulmonary artery occlusion on arterial oxygenation during endobronchial anesthesia. South Med J 69:619, 1976 8. Jenkins AV, Clarke G: Endobronchial anaesthesia with the Carlens catheter. Br J Anaesth 30:13,1958 9. Kerr JH: Physiological aspects of one-lung (endobronchial) anesthesia. Int Anesthesiol Clin 10:61, 1972 10. Kerr JH, Smith AC, Prys-Roberts C, et al: Observations during endobronchial anaesthesia: I. Ventilation and carbon dioxide clearance. Br J Anaesth 45: 159, 1973 11. Kerr JH, Smith AC, Prys-Roberts C, et al: Observations during endobronchial anaesthesia: 11. Oxygenation. Br J Anaesth 46:84, 1974 12. Khanam T, Branthwaite MA: Arterial oxygenation during one-lung anaesthesia (2). Anaesthesia 28:280, 1973 13. Lunding M, Fernandes A: Arterial oxygen ten-

sion and acid-base status during thoracic anesthesia. Acta Anaesthesiol Scand 11:43, 1967 14. NewmanRW, Finer GE, Downs JE: Routineuse of the Carlens double-lumen endobronchial catheter. J Thorac Cardiovasc Surg 42:327, 1961 15. Nilsson E, Slater EM, Greenberg J: The cost of the quiet lung: fluctuation i n Paq when the Carlens tube is used in pulmonary surgery. Acta Anaesthesiol Scand 9:49, 1956 16. Robertshaw FL: Low resistance double-lumen endobronchial tubes. Br J Anaesth 34:576, 1962 17. Tarhan S, Lundborg RO: Blood gas and pH studies during use of the Carlens catheter. Can Anaesth SOCJ 15:458, 1968 18. Tarhan S, Lundborg RO: Effects of increased expiratory pressure on blood gas tensions and pulmonary shunting during thoracotomy with use of the Carlens catheter. Can Anaesth SOCJ 17:4,1970 19. Tarhan S, Lundborg RO: Carlens endobronchial catheter versus regular endotracheal tube during thoracic surgery: a comparison of blood gas tensions and pulmonary shunting. Can Anaesth SOC J 18:594, 1971 20. Thomson DF, Campbell D: Changes in arterial oxygen tension during one-lung anaesthesia. Br J Anaesth 45:611, 1973 21. Torda TA, McCulloch CH, OBrien HD, et al: Pulmonary venous admixture during one-lung anaesthesia. Anaesthesia 29:272, 1974 22. Wood RE, Campbell D, Razzuk MA, et al: Surgical advantages of selective unilateral ventilation. Ann Thorac Surg 14:173, 1972 23. Zeitlin GL, Short DH, Ryder GH: An assessment of Robertshaw double-lumen tube. Br J Anaesth 37:858, 1965

Notice from the American Board of Thoracic Surgery The 1977 annual certifying examination of the 1977. Please address all communications to the American Board of Thoracic Surgery (written American Board of Thoracic Surgery, 14624 E and oral) will be held in Chicago in March, 1978. Seven Mile Rd, Detroit, MI 48205. Final date for filing application was August 1,